[llvm] c8d6351 - [SCEV] Add coverage for howFarToZero w/ non-constant strides

Philip Reames via llvm-commits llvm-commits at lists.llvm.org
Wed Jun 5 11:57:12 PDT 2024


Author: Philip Reames
Date: 2024-06-05T11:57:01-07:00
New Revision: c8d63516ac9e15831975392dd9f6b9ae6a31b21c

URL: https://github.com/llvm/llvm-project/commit/c8d63516ac9e15831975392dd9f6b9ae6a31b21c
DIFF: https://github.com/llvm/llvm-project/commit/c8d63516ac9e15831975392dd9f6b9ae6a31b21c.diff

LOG: [SCEV] Add coverage for howFarToZero w/ non-constant strides

Specifically, cases which require context sensative reasoning which
the current code doesn't do.

Added: 
    

Modified: 
    llvm/test/Analysis/ScalarEvolution/trip-count-unknown-stride.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Analysis/ScalarEvolution/trip-count-unknown-stride.ll b/llvm/test/Analysis/ScalarEvolution/trip-count-unknown-stride.ll
index eb55e6abc95e6..ecf13320a5e81 100644
--- a/llvm/test/Analysis/ScalarEvolution/trip-count-unknown-stride.ll
+++ b/llvm/test/Analysis/ScalarEvolution/trip-count-unknown-stride.ll
@@ -267,7 +267,228 @@ for.end:                                          ; preds = %for.body, %entry
   ret void
 }
 
+define void @ne_nsw_pos_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nsw_pos_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nsw_pos_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %pos_step = icmp sgt i32 %s, 0
+  call void @llvm.assume(i1 %pos_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nsw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nsw_neg_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nsw_neg_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nsw_neg_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %neg_step = icmp slt i32 %s, 0
+  call void @llvm.assume(i1 %neg_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nsw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nsw_nonneg_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nsw_nonneg_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nsw_nonneg_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %nonneg_step = icmp sge i32 %s, 0
+  call void @llvm.assume(i1 %nonneg_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nsw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nsw_unknown_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nsw_unknown_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nsw_unknown_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nsw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nuw_pos_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nuw_pos_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nuw_pos_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %pos_step = icmp sgt i32 %s, 0
+  call void @llvm.assume(i1 %pos_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nuw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nuw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nuw_neg_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nuw_neg_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nuw_neg_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %neg_step = icmp slt i32 %s, 0
+  call void @llvm.assume(i1 %neg_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nuw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nuw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nuw_nonneg_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nuw_nonneg_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nuw_nonneg_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %nonneg_step = icmp sge i32 %s, 0
+  call void @llvm.assume(i1 %nonneg_step)
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nuw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nuw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
+define void @ne_nuw_unknown_step(ptr nocapture %A, i32 %n, i32 %s) mustprogress {
+;
+; CHECK-LABEL: 'ne_nuw_unknown_step'
+; CHECK-NEXT:  Determining loop execution counts for: @ne_nuw_unknown_step
+; CHECK-NEXT:  Loop %for.body: Unpredictable backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable constant max backedge-taken count.
+; CHECK-NEXT:  Loop %for.body: Unpredictable symbolic max backedge-taken count.
+;
+entry:
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, ptr %A, i32 %i.05
+  %0 = load i32, ptr %arrayidx, align 4
+  %inc = add nuw i32 %0, 1
+  store i32 %inc, ptr %arrayidx, align 4
+  %add = add nuw i32 %i.05, %s
+  %cmp = icmp ne i32 %add, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+
 
+declare void @llvm.assume(i1)
 
 !8 = distinct !{!8, !9}
 !9 = !{!"llvm.loop.mustprogress"}


        


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